In the view of police investigators, the recording was "most likely" on purpose, but at the least "reckless".

The letter to Key and Banks from Ambrose was "one of the factors that we took into account" and his lack of a criminal record was another.

Burgess said he would still advise media organisations not to play the tape.

Asked why the inquiry took so long, Burgess said it took time to talk to those involved, particularly members of public who were in the cafe.

Police had focused on Ambrose's action and not publication of the tape online earlier this year, he added.

Key said he welcomed the police decision and also welcomed Ambrose's "letter of regret".

"I note that the police statement today contains the comment that, while Mr Ambrose has been issued a warning, the police are clear that his actions were unlawful.

"As the complainant in this matter, my views were sought by the Crown Solicitor on whether I thought Mr Ambrose should be prosecuted. In light of Mr Ambrose's letter of regret, I indicated that I did not believe a prosecution was now necessary.

"I repeatedly said at the time that I was concentrated on the issues that matter to the New Zealand public, and that the secret recording wasn't one of those issues. That remains the case.

"The decision announced by the police today, and Mr Ambrose's letter, allow all concerned to move on from the situation."

THE APOLOGY

In his letter Ambrose stated:

"As you are aware I attended your media meeting at the Urban Caf6, Newmarket. I was paid a small fixed fee to film the event for the Herald Online News, Webb Page. I was working alone on this occasion.

"My camera radio microphone was left on your cafe table. It had been placed there by me in a rush to pick up audio while you were speaking to the media. I had not expected this and was not prepared for it.

"I was having difficulty getting good footage due to the media scrum around you. So I moved off and away from the table area to try and get some workable footage from a different vantage point. In doing so I left the microphone on the table. My primary concern was to get film footage.

"When I later realised that I had left the microphone behind I returned to uplift it. I spoke to your staff who acknowledged they had taken possession of it, that it would not be returned and would be referred to the police. I did not realise at that time what the concern was and or why. I had no intention of secretly recording any conversation.

"Later that day when the existence of the recording became public I was requested to pass on what I had recorded. I accept that I did so without thinking properly about the effect this would have. I regret this decision.

"As stated I do regret passing this audio on to the Herald on Sunday due to the effects that this had had on those involved including yourself. Contrary to what has been said by some people, this was not intentional, nor was it a

"News of the World tactic". There was no money offered for the recording by the Herald on Sunday nor did they or any other outlet pay for it.

"This whole event has been blown out of proportion by a number of people and I would like to put it behind me.

"I just want to get back to work and not be known as someone alleged to have dubious ethics.

"This has been hard on me and my family. I trust that you are prepared to accept and appreciate my regret for how this matter has unfolded and escalated for us all. If I knew then what I know now, I would have deleted the tape at the first opportunity and not provided it to any other third party. I have become much wiser and more protective of my reputation as a result of this event and what has transpired.

"Accordingly I trust that you find this letter as a genuine statement of regret."